1. Technical Field
The present invention relates to an image forming apparatus for processing data transmitted to and received from a host and, more particularly, to a host interface circuit for interfacing parallel data received from a host.
2. Related Art
Generally, an image forming apparatus, (for example, a printer) is connected to a host (such as a personal computer) so as to transmit and receive data from the host. The image forming apparatus includes a host interface circuit for interfacing the data transmitted to and received from the host.
In such conventional arrangements, the host interface circuit is often used in a low-speed image forming apparatus and is connected to a high-speed host to receive data therefrom. In such an arrangement, the host can transmit data before the image forming apparatus has a chance to generate a busy signal after transmission of one byte of data by the host. Thus, the data can collide with previous data, resulting in the inadvertent loss of data.
The following patents are considered to be representative of the prior art relative to the invention disclosed herein, and are burdened by the disadvantages discussed above.: U.S. Pat. No. 5,671,445 to Gluyas et al., entitled Interface For Transmitting Graphics Data To A Printer From A Host Computer System In Rasterized Form, U.S. Pat. No. 5,640,571 to Hedges et al., entitled Interrupt Steering For A Computer System, U.S. Pat. No. 5,630,094 to Hayek et al., entitled Integrated Bus Bridge And Memory Controller That Enables Data Streaming To A Shared Memory Of A Computer System Using Snoop Ahead Transactions, U.S. Pat. No. 5,615,390 to Kurahara, entitled System For Determining And Controlling The Input/Output Mode Of Input/Output Terminal Of Microcomputer Using Reset Signal Change Point Detection Circuit, U.S. Pat. No. 5,608,883 to Kando et al., entitled Adapter For Interconnecting Single-Ended And Differential SCSI Buses To Prevent `Busy` Or `Wired-OR` Glitches From Being Passed From One Bus To The Other, U.S. Pat. No. 5,604,608 to Walsh et al., entitled Device And Method For Controlling The Scan Speed Of An Image Input Terminal To Match The Throughput Constraints Of An Image Processing Module, U.S. Pat. No. 5,577,213 to Avery et al., entitled Multi-Device Adapter Card For Computer, U.S. Pat. No. 5,572,691 to Koudmani, entitled Apparatus And Method For Providing Multiple Data Streams From Stored Data Using Dual Memory Buffers, U.S. Pat. No. 5,163,132 to DuLac et al., entitled Integrated Controller Using Alternately Filled And Emptied Buffers For Controlling Bi-Directional Data Transfer Between a Processor And A Data Storage Device, and U.S. Pat. No. 4,750,107 to Buggert, entitled Printer-Tape Data Link Processor With DMA Slave Controller Which Automatically Switches Between Dual Output Control Data Chomels.